Fall Out Boy didn’t become Reading’s new unofficial house band by default. Sure, My Chemical Romance’s departure right before they could inherit the throne left a vacancy, but in an era where Foo Fighters’ meat and potato FM radio rock no longer plays to anyone under the age of 30, the usual parade of one dimensional pretenders were never going to fit.

As the festival itself shifts from a monochrome alt-rock spectrum to a rainbow of genres and influences, it’s struggled to always find the headliners to fit. Tomorrow night’s booking of Kendrick Lamar quite rightly no longer feels in any way brave - how could one of the biggest artists on the planet feel like a gamble - but it’s still a new departure for Reading. With an uninspired, uninspiring Kings of Leon in place for Sunday, Fall Out Boy become the steady hands, and yet they also understand exactly what’s required for the occasion.

Since returning from their early grave, they’re a band who have constantly played with expectation. Their pop punk roots have given fruit to albums that draw just as much influence from a mainstream landscape where rock has receded, giving way to hip hop and electronic music. It’s an experiment that doesn’t always sit comfortably - but crucially refuses to stay still and rest on the expected.

With all that said, the fact the band quite happily drop their biggest payload four songs into their set still feels like a surprise. ‘Sugar, We’re Goin Down’ may be an echo to Fall Out Boy’s old world, but it’s part of the foundations on which Reading is built upon. While more timid bands would take that energy and feed it with a parade of ‘classic’ greatest hits, they instead push down the accelerator and blast through a run largely consisting of v2.0 bombast. From the triumphant ‘Immortals’ to the batshit ‘Stay Frosty Royal Milk Tea’, the pulp fiction of ‘Uma Thurman’ and the epic ‘Save Rock and Roll’, it shows an understanding of where alternative music really stands in 2018.

That’s not to say they’re a band denying the classics. The second half of their set embraces that history. From the zombie disco of ‘Dance, Dance’ to ‘This Ain’t A Scene…’ - quite possibly the song where Fall Out Boy’s future mutations showed their first green shoots - each feels like a commandment from on high. The sepia tinged nostalgia of encore closer ‘Saturday’ (complete with Pete Wentz’ retro Alan Shearer England shirt) is proof that for all the talk of musical change, Reading 2018 requires both sides of the coin to thrive. Still, fundamentally, a rock festival, it’s not simply a case of booking a bunch of disparate acts and hoping the constantly shifting sound of playlist culture makes it stick. Bands like Fall Out Boy provide the bridge that takes a genre-less world and pulls the strands together. Whether they’re leading the way or following the trends, Reading’s biggest slot is where Fall Out Boy belong.